As a luminescent electronic display, there is an electroluminescent display (ELD). The constituent element of the ELD includes an inorganic or organic electroluminescent device (hereinafter, referred to as an inorganic or organic EL device). The inorganic EL device has been used as a flat-shaped light source, but an alternating high-voltage is needed to drive a light-emitting device. The organic EL device has a constitution in which a light-emitting layer containing a light-emitting compound is sandwiched between a cathode and an anode. The organic EL device emits light using emission of light (fluorescence•phosphorescence) caused by deactivation of excitons that are generated by injecting electrons and positive holes into the light-emitting layer followed by making them recombine. The organic EL device is able to emit light at a voltage of from about several V to about several tens of V. Further, due to a self-luminescent type, the organic EL device has good viewing angle and a high level of visibility, and due to a thin-film type absolute solid-state device, the organic EL device has attracted attention from viewpoints of reduced space and portability.
The organic EL device is a polycrystalline semiconductor device and can emits a high-intensity luminescence with a low voltage. The organic EL device is therefore used for a backlight of the liquid crystal and the like and has been expected to be a thin-flat display device. However, the organic EL device has drawbacks such that due to a terrible susceptibility to moisture, the interface between a metal electrode and an organic EL layer breaks away under the influence of moisture, a metal is oxidized to become highly resistive, an organic component itself becomes modified by moisture, and given this situation, emission of light does not occur or luminance becomes lowered.
The organic EL device has a property such that light-emitting characteristics deteriorate upon exposure to moisture and the like contained in atmospheric air. Therefore, in order to bring the organic EL panel into operation stably for a long time, a sealing structure for blocking the organic EL device from atmospheric air is absolutely imperative. As the sealing structure of the organic EL panel, a structure (hollow sealing structure) in which a sealing member made from metal or glass and a substrate on which an organic EL device has been formed are stuck together to form a sealing space surrounding the organic EL device and further a drying agent is disposed in the sealing space, has been adopted in general. However, in consideration of making the panel more thinner and improving mechanical strength or the like, studies on a solid sealing structure in which the organic EL device is directly coated with a sealing material without a space has been conducted (refer to Patent Literature 1). Further, recently a method is proposed in which a drying agent is added to a sealing material and the resultant material is provided on the organic EL device in the form of lamination, thereby protecting the organic EL device from influence of moisture (refer to Patent Literatures 2 and 3).
However, even in the case of adding a drying agent to a resin as mentioned above, it is impossible to suppress movement of moisture in the resin in a sufficient degree, and it has not sufficiently achieved to improve deterioration due to display defects, so-called dark-spot, in which emission of light is not obtained at the non-luminous point and around the light-emitting face.